Preheat oven to 400 degrees. In bowl, whisk together all the eggs, parmesan cheese, dried basil, salt and pepper.
Stir in cooked potatoes, ham. reserve.
In ovenproof 10" nonstick skillet, heat oil over medium heat. Add chopped onion. Cook, stirring occasionally, until browned and almost tender. Stir in thawed spinach or other leftover veggies. Cook until heated through about 1 minute. Increase heat to medium-high. Stir in reserved egg mixture; cook until edges are set, about 2-3 minutes. Place in oven. Bake 15 minutes or until center is set.